SEGMENT REPORTING (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012	Apr. 30, 2013	Apr. 30, 2012
Segment revenues and net operating income [Abstract]
Real estate revenue	$ 66,190	$ 62,258	$ 131,697	$ 121,603
Real estate expenses	26,515	24,049	53,339	48,114
Gain on involuntary conversion	0	2,263	966	2,263
Net operating income	39,675	40,472	79,324	75,752
Depreciation/amortization	(17,257)	(15,758)	(36,352)	(31,201)
Administrative, advisory and trustee services	(2,527)	(2,061)	(5,280)	(4,157)
Impairment of real estate investments			(265)
Other expenses	(678)	(513)	(1,357)	(1,032)
Interest expense	(14,848)	(15,727)	(29,500)	(31,544)
Interest and other income	652	203	862	345
Income from continuing operations	5,017	6,616	7,432	8,163
Income from discontinued operations	5,280	3,394	6,081	3,843
Net income	10,297	10,010	13,513	12,006
Segment Assets [Abstract]
Property owned	2,032,747		2,032,747		2,032,970
Less accumulated depreciation	(431,318)		(431,318)		(420,421)
Net property owned	1,601,429		1,601,429		1,612,549
Real Estate Held-for-sale	2,620		2,620		0
Cash and cash equivalents	68,727	84,258	68,727	84,258	94,133	39,989
Other investments	642		642		639
Receivables and other assets	111,158		111,158		113,948
Development in progress	90,052		90,052		46,782
Unimproved land	21,619		21,619		21,503
Total Assets	1,896,247		1,896,247		1,889,554
Multi-Family Residential [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	25,652	23,105	50,234	44,314
Real estate expenses	11,275	9,009	22,234	18,301
Gain on involuntary conversion		2,263	966	2,263
Net operating income	14,377	16,359	28,966	28,276
Segment Assets [Abstract]
Property owned	722,099		722,099		659,696
Less accumulated depreciation	(150,427)		(150,427)		(140,354)
Net property owned	571,672		571,672		519,342
Commercial-Office [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	19,367	18,815	38,681	37,169
Real estate expenses	9,525	9,196	19,278	18,321
Gain on involuntary conversion		0	0	0
Net operating income	9,842	9,619	19,403	18,848
Segment Assets [Abstract]
Property owned	610,183		610,183		613,775
Less accumulated depreciation	(143,136)		(143,136)		(138,270)
Net property owned	467,047		467,047		475,505
Commercial-Healthcare [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	16,025	15,262	32,098	30,334
Real estate expenses	4,129	4,180	8,412	8,259
Gain on involuntary conversion		0	0	0
Net operating income	11,896	11,082	23,686	22,075
Segment Assets [Abstract]
Property owned	515,423		515,423		501,191
Less accumulated depreciation	(98,275)		(98,275)		(90,891)
Net property owned	417,148		417,148		410,300
Commercial-Industrial [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	1,743	1,716	3,953	3,300
Real estate expenses	548	455	1,052	944
Gain on involuntary conversion		0	0	0
Net operating income	1,195	1,261	2,901	2,356
Segment Assets [Abstract]
Property owned	67,016		67,016		125,772
Less accumulated depreciation	(12,467)		(12,467)		(23,688)
Net property owned	54,549		54,549		102,084
Commercial-Retail [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	3,403	3,360	6,731	6,486
Real estate expenses	1,038	1,209	2,363	2,289
Gain on involuntary conversion		0	0	0
Net operating income	2,365	2,151	4,368	4,197
Segment Assets [Abstract]
Property owned	118,026		118,026		132,536
Less accumulated depreciation	(27,013)		(27,013)		(27,218)
Net property owned	$ 91,013		$ 91,013		$ 105,318